Nationality: United StatesExecutive summary: ENIAC, BINAC, and UNIVAC I computers

Electrical engineer and inventor John Presper Eckert — family and friends called him Pres — was the co-designer of the ENIAC, the first general-purpose electronic digital computer, with John William Mauchly. The 30-ton ENIAC (Electronic Numerical Integrator and Computer) utilized over 10,000 capacitors, 17,500 vacuum tubes, 70,000 resistors, and half a million soldered connections. The "software" was not at all soft, as each program was defined in weighty, hard-wired panels that were disconnected and replaced to change the machine's functions. It used a mercury delay line memory invented by Eckert, in which liquid mercury tubes several feet long converted electrical pulses to sound and then back to electricity. ENIAC's computing ability was estimated to be a thousand times more than any previous machine, though of course it was effectively negligible next to a modern-day PC or Macintosh.

Eckert and Mauchly first collaborated at the University of Pennsylvania's Moore School of Electrical Engineering, and their ENIAC passed its first operational tests in late 1945, but they left in 1946 when the University enacted a new rule claiming patent ownership over employee projects. They started the Electronic Control Company (later renamed the Eckert-Mauchly Computer Company) in the same year, and their second computer, BINAC (Binary Automatic Computer), became operational in 1949, pioneering the use of magnetic tape instead of punch cards for data storage.

For their most famous project, the Universal Automatic Computer (UNIVAC), Eckert focused on the hardware while Mauchly worked on software applications. UNIVAC was delayed by recurring design and funding problems, but the first UNIVAC was delivered to the US Census Bureau in 1951. It was the first manufactured computer used for mundane payroll and accounting purposes in commercial settings, but made its biggest headlines for correctly predicting Dwight D. Eisenhower as winner of the 1952 Presidential election for CBS News less than an hour after polls closed, while less than 1% of ballots had actually been counted. Eckert and Mauchly also designed and built EDVAC (the Electronic Discrete Variable Automatic Computer) in 1952, which boasted its own internal memory and used less than 4,000 vacuum tubes.

In 1950 the Eckert-Mauchly Computer Company was purchased by Remington Rand, a maker of typewriters and office machines, which was later merged into the former Burroughs Corporation to become Unisys. The first-generation UNIVAC began being phased out from use in the mid 1950s, but subsequent models remained at the cutting edge of computer technology well into the 1970s. Eckert was employed at Unisys for the rest of his career, and held almost a hundred patents. In a 1970s lawsuit between corporate titans Honeywell and Sperry-Rand (a later Unisys ancestor), however, Eckert and Mauchly's patent for ENIAC was invalidated, and John Atanasoff was deemed to have been the actual inventor of the modern computer.

Eckert was said to have done his best engineering work by speaking instead of writing, effectively thinking out loud, and preferred to have an audience for this process, though it did not matter to him who the audience was — a random stranger was, for his purpose, as good as anyone. His father was wealthy, making millions as a real estate developer and speculator, and the family's friends included movie star Douglas Fairbanks, Sr. and television pioneer Philo Farnsworth.